//html font-size 自适应
var rem=100;
(function (doc, win) {
    var docEl = doc.documentElement,
        resizeEvt = 'orientationchange' in window ? 'orientationchange' : 'resize',
        recalc = function () {
            flex(rem,1)
        };
    if (!doc.addEventListener) return;
    win.addEventListener(resizeEvt, recalc, false);
    doc.addEventListener('DOMContentLoaded', recalc, false);
})(document, window);
/**
 * @param {Number} [baseFontSize = 100] - 基础fontSize, 默认100px;
 * @param {Number} [fontscale = 1] - 有的业务希望能放大一定比例的字体;
 */
var win = window;
win.flex = (baseFontSize, fontscale) => {
    var _baseFontSize = baseFontSize || 100;
    var _fontscale = fontscale || 1;
    var doc = win.document;
    var ua = navigator.userAgent;
    var matches = ua.match(/Android[\S\s]+AppleWebkit\/(\d{3})/i);
    var UCversion = ua.match(/U3\/((\d+|\.){5,})/i);
    var isUCHd = UCversion && parseInt(UCversion[1].split('.').join(''), 10) >= 80;
    var isIos = navigator.appVersion.match(/(iphone|ipad|ipod)/gi);
    let dpr = win.devicePixelRatio || 1;
    if (!isIos && !(matches && matches[1] > 534) && !isUCHd) {
        // 如果非iOS, 非Android4.3以上, 非UC内核, 就不执行高清, dpr设为1;
        dpr = 1;
    }
    var scale = 1 / dpr;
    var metaEl = doc.querySelector('meta[name="viewport"]');
    if (!metaEl) {
        metaEl = doc.createElement('meta');
        metaEl.setAttribute('name', 'viewport');
        doc.head.appendChild(metaEl);
    }
    metaEl.setAttribute('content', `width=device-width,user-scalable=no,initial-scale=${scale},maximum-scale=${scale},minimum-scale=${scale}`);
    doc.documentElement.style.fontSize = `${_baseFontSize / 2 * dpr * _fontscale}px`;
};